Circuit breaker operating mechanism having torsion bar springs

ABSTRACT

A circuit breaker operating mechanism comprises one or more supporting frame members on which a movable contact operating means, including a collapsible toggle linkage, is mounted. One or more torsion bars, each having a fixed end attached to a frame member and a rotatable working end, are mounted on the frame members. A pivotable member or crank on the frame members cooperates with the toggle linkage and the working end of the torsion bar. A manually operable handle or motor-driven cam moves the crank to a position wherein it allows the toggle linkage to assume its contact open position and wherein the crank charges the torsion bar. A releasable latching means holds the crank in such position until it is released, whereupon the torsion bar rotates the crank which, in turn, moves the toggle linkage to contact closed position.

United States Patent [72] Inventor Edwin C. Goodwin, Jr.

Canton, Mass.

[21 Appl. No. 874,460

[22] Filed Nov. 6, I969 [45] Patented Aug. 17, I971 [73] Assignee Allis-Chalmers Manufacturing Company Milwaukee, Wis.

[54] ClRCUlT BREAKER OPERATING MECHANISM HAVING TORSION BAR SPRINGS 14 Claims, 13 Drawing Figs.

[52] U.S. Cl 200/153, 200/154, 200/169 l5l| lnt.Cl H0lh 3/00 [50] Field 0! Search .i 74/97;

ZOO/153.8, l53.7, 61.76, 148, I54, 169; 335/l 89,

Primary Examiner-D. F. Duggan Assistant Examiner-Ulysses Weldon.

Attorneys-Thomas F. Kirby, Lee H. Kaiser and Robert B.

Benson ABSTRACT: A circuit breaker operating mechanism comprises one or more supporting frame members on which a movable contact operating means, including a collapsible toggle linkage, is mounted. One or more torsion bars, each having a fixed end attached to a frame member and a rotatable working end, are mounted on the frame members. A pivotable member or crank on the frame members cooperates with the toggle linkage and the working end of the torsion bar. A manually operable handle or motor-driven cam moves the crank to a position wherein it allows the toggle linkage to assume its contact open position and wherein the crank charges the torsion bar. A releasable latching means holds the crank in such position until it is released, whereupon the torsion har rotates the crank which, in turn, moves the toggle linkage to contact closed position.

CIRCUIT BREAKER OPERATING MECHANISM HAVING TORSION BAR SPRINGS BACKGROUND OF THE INVENTION Field of the Invention Thisinvention relates generally to electric circuit breaker contact operating mechanisms using torsion bars as a stored energy means to move the circuit breaker contacts to operatsion bar of essentially the same forcecharacteristics.

SUMMARY OF THE INVENTION The present invention contemplates a circuit breaker contact operating mechanism having supporting means comprising one or more frame members, contact operating means including a linkage and other components movable to alternative positions on said supporting means, torsion bar means on said supporting means comprising one ormorc torsion bars each having a fixed end attached to the supporting means and a rotatableworking end, a movable member such as a crank on said supporting means for cooperation with said contact operating means to effect operation thereof and the working end of said torsion bar to charge the latter, means such as a manually operable lever or motor-driven cam to move said crank to one position wherein it maintains said contact operatingmeans in oneposition and charges said torsion bar, and releasable; latching means on said supporting means to maintain' said crank in said one position against the force of said torsion bar.

OBJECTS OF THE INVENTION Objects of the invention are to provide improved circuit breaker contact operating mechanisms; to provide improved stored energy means for such mechanisms; to provide improved circuit breaker operating springs in the form of torsion bars which have less inherent stress, which are more compact and less costly, which have longer life, and have more reliable operating characteristics than conventional springs; and to provide improved circuit breaker contact closing springs.

DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrate several preferred embodiments of the invention which, it is to be understood, can be modified with respect to details without departing from the scope of the appended claims.

In the drawings:

FIG. 1 is a side elevational view of a circuit breaker operatingmechanismaccording to a first embodiment of the inven tron;

FIG. 2 is a sectional view-taken along line II-'-II of FIG. 1;

FIG. 3 is a side elevational view of a circuit breaker operating mechanism according to a second embodiment of the invention; 1

FIG. 4 is a sectional view taken along line- IV-IV of FIG. 3;

FIG. 5 is a side elevational view-of a circuit breaker operating mechanism according to a third embodiment of the invention;

FIG."6 is a sectional view taken along line VIVI of FIG. 5;

FIG. 7 is a side. elevational view ofa circuit breaker operating mechanism according to a fourth embodiment of the invention;

FIG. 8 is a sectional view taken along line VIII-VIII of FIG.

FIG. 9 is a side elevational view of a circuit breaker operating mechanism according to a fifth embodiment of the invention;

FIG. 10 is an end view, partly in phantom, of a portion of the operating mechanism of FIG. 9;

FIG. 11 is a side elevational view of a circuit breaker operating mechanism according to a sixth. embodiment of the invention;

FIG. 12 is an end view of a portion of the operating mechanism of FIG. 11; and

FIG. 13 is an isometric view of a bearing from the mechanism of FIGS. 11 and 12.

DESCRIPTION OF THE PREFERRED EMBODIMENT First Embodiment FIGS. 1 and 2 showa circuit breaker contact operating mechanism 10 for opening and closing a pair of relatively movable contacts 12 and 14. Mechanism 10 comprises a supporting means 15 in the form of a pair of substantially flat spaced-apart frame members 16 and 17 on which a movable contact arm 18 is pivotably mounted. Contact arm 18 carries movable contact 12 and a suitable structure 20, which is understood to be in fixed relationship to the aforesaid support, carries stationary contact 14.

Contact operating means are provided to move contact arm 18 to its open and closed contact operating positions and comprise stored energy means such as a contact opening spring 22 which is connected between supporting means 15 and contact arm 18 and tends to bias the latter clockwise with respect to FIG. 1. The contact operating means further comprise a linkage 24 which is carried on supporting means 15 between frames 16 and 17. Linkage 24 comprises a pair of toggle links 26 and 28 which are pivotably connected at adjacent ends by a pin 30 on which a toggle roller 32 is rotatably mounted. Link 26 is pivotably connected at its other end to one end of an arm 34 by a pin 36 on which a trip latch roller 38 is rotatably mounted. The other end of arm 34 is pivotably connected to a pin 40 on supporting means 15. Link 28 is pivotably connected at its other end to contact arm 18 by a'pin 41. Linkage 24 is shown in contact open position and is movable overcenter to a contact closed position wherein its toggle roller 32 rests against a stop 48 onsupporting means 15 and wherein arm 34 and the togglelinks 26 and 28 are nearly aligned.

Linkage 24 is movable overcenter by a movable means such as a crank member 54 which is pivotably mounted on pin 40 between frame members 16 and 17 and cooperates with the linkage. Linkage 24 and crank 54 move in planes which are substantially parallel to the planes inwhich the frame members 16 and 17 liesCrank 54' has a roller 50which is rotatably mounted on a pin 52 and is adaptedto engage toggle roller 32 when the crank moves clockwise. (Crank 54 has a trunnion block62'rotatably mountedon a pin 64 and is adapted to engage a roller 66 on a torsion bar 70of a torsion bar means 23. Crank 54 has means such as a slot'5 5 for engaging a removable handle57 which is used to manually reset mechanism 10. As hereinafter explained, cr'ank54 cooperates with torsion bar means 23 to effect charging of the latter.

Releasable latching means are provided to maintain the contact operatingmeans in open and closed operating positions. Thus, a releasable trip latch 42 is pivotably mounted on support means 15 and bears against trip latch roller 38. Latch 42 is movable clockwise to tripped or released position by a plunger 44 of a trip solenoid 46 when the latter is energized. Crank 54 is latched against clockwise rotation under the force of torsion bar means 23 by'a prop latch 56 which is pivotably mountedon supporting means 15 and bears against roller 50. Prop latch 56 is movable clockwise to unlatched or released positionby a plunger 58 of a closing solenoid 60 when the latter is energized.

The torsion bar closing means 23, hereinbefore referred to, comprises torsion bar 70 which is in the form of an elongated cylindrical-rod which has a first or fixed end and a second or working end and is supported between frame members 16 and 17 on frame member 16 by bearings 68 which engage the midportion of the bar and allow for its rotation about its axis. The axis of bar 70 is parallel to frame member 16. Means are provided to secure the fixed end of bar 70 to the support. Thus, the fixed end of torsion bar 70 is bent to provide a portion 72 which engages a hole 74 in frame member 17 and by this means the bar is securely anchored to supporting means 15. The working end of torsion bar 70 is U-shaped and comprises a short leg or means 76 which is offset from and parallel to the axis of midportion of the bar and on which roller 66 is rotatably mounted. Leg 76 and roller 66 thereon are adapted to rotate about the axis of torsion bar 70 as the latter twists during charging and discharging thereof.

Circuit breaker operatingmechanism 10 operates as follows. Assume initially that its components are disposed in contact open position, as shown in FIGS. 1 and 2, and that torsion bar 70 is twisted t the position shown and is, therefore, charged.

To close contacts 12 and 14, closing solenoid 60 is energized and its plunger 58 rotates prop latch 56 clockwise to unlatched position thereby freeing crank 54 for clockwise rotation. As torsion bar 70 untwists counterclockwise (with respect to FIG. 2), roller 66 on torsion bar 70 bears against the lower surface of trunnion block 62 and rotates crank 54 rapidly and forcefully. Roller 50 on crank 54 strikes toggle roller 32 and forces toggle linkage 24 to overcenter position wherein roller 32 comes to rest against stop 48 and wherein contact arm 18 is forced counterclockwise to contact closed position by the extended toggle linkage and the contacts 12 and 14 engage. As contact arm 18 is moved upward it effects charging of opening spring 22.

To open contact 12 and 14, trip solenoid 46 is energized and its plunger 44 rotates trip latch 42 clockwise to unlatched position out of engagement with trip latch roller 38. This allows arm 34 to be rotated clockwise and toggle linkage 24 collapses thereby allowing contact arm'18 to move downward under the action of opening spring 22 and causing contacts 12 and 14 to separate. v

To reset mechanism 10, handle 57 is inserted in slot 55 of crank 54 and is pushed downwardly to rotate crank 54 counterclockwise thereby causing torsion bar 70 to be twisted clockwise (with respect to FIG. 2) and recharged. As crank 54 is rotated, prop latch 56 reengages roller 50 and holds the crank in the position shown. As crank 54 moves back to the position shown, a spring not shown acting on contact arm 34 forces togglelinkage 24 and arm 34 to the position shown and trip latch 42 reengages trip latch roller 38.

Crank 54 and linkage 24 move in the plane or planes in which the frame members lie, which planes are transverse to the plane in which the working end of torsion bar 70 rotates.

SECOND EMBODIMENT FIGS. 3 and 4 show a second circuit breaker contact mechanism 110 which is generally similar to mechanism but differs therefrom in certain respects, as hereinafter explained. In FIGS. 3 and 4, elements in mechanism '110 are designated by the same reference numbers as similar elements in mechanism 10. Mechanism 110 employs a supporting means which has a single substantially flat frame member 1 16 instead of two frame members as in mechanism 10. Furthermore, mechanism 110 employs a movable means such as a cranking means 154 which comprises several members or links instead-of a single crank member 54, as in mechanism 10. Cranking means 154 comprise a first link 1540 which is pivotally connected at one end by pin 40 to link 34. Link 1540 carries roller 50 which cooperates with latch 56 and roller 32. Link 154a is'pivotally connected by pin 52 to a second link 154b which, in turn, is pivotally connected to a third link 1540.

-Link 154b carries roller 155 which travels alongside a clearance slot 157 in frame member 116 and is adapted to cooperate with a cam 158. A roller and cam on each side of the frame may also be used. Link l54c-is pivotally attached to frame member 116 at a point 140. Link 1540 carries a trunnion block 62 for engagement with roller 66 on torsion bar spring 70. Supporting frame '116 is provided with an opening 156 wherein trunnion block 62 and roller; 66 can move. As FIG. 4 shows, link 154a comprises two spacedapart members, one on each side of frame member 116,; between which block 62 is mounted. p I

Cranking means 154 of mechanism is shown latched in contact open position. Release of prop. latch 56 allows crank 154 to be moved to contact closed position by the action of roller 66 of torsion bar 70 on trunnion block 62 which moves link 154c clockwise, link 1541: to the right and link 154a clockwise, such movements being with respect to FIG. 3.

Mechanism 110 is provided with a motor 159 and cam 158 driven thereby which operate to reset mechanism 110 as the cam rotates counterclockwise to engage roller 155 on link 154b thereby moving the latter to the left and causing links 154a and 154C to pivot counterclockwise. Counterclockwise rotation of cam 158 terminates somewhat before the cam reaches the position shown in FIG. 3 wherein it operates a limit switch 160 which controls motor 159. Thus, torsion bar 70 is recharged as mechanism 110 is reset.

One advantage of mechanism 110 is that its supporting means comprises only a single frame member on opposite sides of which, and in openings provided therein, the componentsof the mechanism are symmetrically and compactly arranged.

It is to be understood that the other embodiments of the invention hereinafter described contemplate circuit breaker operating mechanisms generally similar to mechanism 110 hereinbefore described but differ therefrom with respect to the number of torsion bars employed, the manner of their attachment to the supporting means, and the means by which the torsion bars cooperate with the movable member'crank.

Third Embodiment FIGS. 5 and 6 show a third circuit breaker contact mechanism 210 which employs two torsion bars and 270 which are identical to torsion bar 70 hereinbefore described. As FIG. 6 shows, the bars 170 and 270 are disposed on opposite sides of single frame member 116 in mechanism 210, but both rollers 166 and 266 thereon cooperate with a single elongated trunnion block 162 on cranking means 154. The advantage of mechanism 210 is that torsion bar forces are doubled while overall compactness is retained.

Fourth Embodiment FIGS. 7 and 8 show a fourth circuit breaker contact mechanism 310 which employs different torsion bars, different means whereby the torsion bars are secured to frame member 116 of the support, and different means whereby the torsion bars cooperate with cranking means 154. Specifically, mechanism 310 comprises two torsion bars 370 and 372, each of which are U-shaped at their fixed end. Each fixed end engages a plate 374 which is rigidly secured to and disposed perpendicularly to frame member 116 as by welding.

Link 1540 carries a trunnion block 362 which has pins 376 and 378 on opposite sides thereof. Torsion bar 370 carries two links 380 and 382 on the short legs of its working end which engage the pins 376 and 378, respectively. Torsion bar 372 carries two similar links 384 and 386 which also engage the pins 376 and 378 respectively. As FIG. 8 shows, the links 380, 382 and 384, 386 do not assume an overcenter position.

Fifth Embodiment FIGS. 9 and 10 show a fifth circuit breaker contact mechanism 410 similar to mechanism 310 but so arranged and dimensioned that its links 480, 482 and 484, 486 assume an overcenter position when the mechanism is in open condition. With such an arrangement a prop latch such as 56 used in mechanism 310 is not required l-lowever, a means is required to unlock or break this overcenter condition before the torsion bars 370 and 372 can release their stored energy and such means take the form of a release latch or lever 490 which pivots counterclockwise (with respect to FIG. 9) when its solenoid 492 is operated.

Sixth Embodiment FIGS. 11 and 12 show a sixth circuit breaker mechanism 510 similar to mechanism 410 but employing another type of means for securing the fixed ends of its torsion bars 470 and 472 to the support. As FIGS. 11 and 12 show, a plate 474 is rigidly secured to frame member 116. Plate 474 is provided with a pair of eyebolts 476 and 478 which engage the midloop portions of the fixed end portions of the torsion bars 470 and 472, respectively. Plate 474 is further provided with a rigidly attached bracket 480 which carries a pair of eyebolts 482 and 484 which engage the end loop portions of the bars 470 and 472, respectively. Eyebolts 476 and 478 are separately adjustable parallel to the frame to accurately position the working. ends of the torsion bars. Eyebolts 482 and 484 are separately adjustable lateral to the frame to provide means for obtaining an equal closing force at the roller, for each torsion bar.

FIGS. 11. and 13 show an improved bracket 500 having holes 502 therein by which it is secured to the side of frame member 116. Bracket 500 is further provided with a pair of projections 504 and 506, which are provided with slots 508 and 510, respectively, which are reversely disposed with respect to one another. in use, a torsion bar is placed in a space 512 between the projections 504 and 506 and the bracket 500 is rotated so that the slots 508 and 510 engage the torsion bar.

The embodiments of the invention in which I claim an exclusive property or privilege are as follows:

1. in a circuitbreaker having supporting means comprising at least one frame member and movable crank means movable toward one position to effect movement of contact operating means in one direction, said crank means being movable to another releasably latchable position which allows the contact operating means to move in another direction, the combination of at least one torsion bar having at least one portion fixed with respect to said supporting means and having a rotatable portion for cooperation with said crank means, said torsion bar being chargeable by movement of said crank means to said other position and said torsion bar effecting movement of said crank means to said one position when the latter is released, said rotatable portion of said torsion bar being rotatable transversely to the direction in which said crank means moves.

2. A circuit breaker according to claim 1 wherein said supporting means comprises a pair of spaced-apart frame members, wherein said contact operating means is disposed substantially between said frame members, and wherein said torsion bar is disposed between said frame members.

3. A circuit breaker according to claim 1 wherein said supporting means comprises a single frame member, wherein said contact operating means is disposed substantially on either side of said frame member, and wherein said torsion bar is disposed on one side of said frame member.

4. A circuit breaker according to claim 3 comprising two torsion bars disposed on opposite sides of said frame member.

5. A circuit breaker according to claim 2 wherein said torsion bar carries a roller on its working end for engagement with a trunnion block on said movable means.

6. A circuit breaker according to claim 4 wherein each of said torsion bars carries a roller on its working end for engagement with a trunnion block on said movable means.

7. A circuit breaker according to claim 3 wherein the working end of said torsion bar is connected to said movable means by at least one link.

8. A circuit breaker according to claim 7 wherein said link assumes an overcenter position with :respect to said torsion bar and said movable means when said movable means 1s moved to said one position and further comprising unlocking means on said support for releasing said link from its overcenter position.

9. A circuit breaker according to claim 4 wherein the working end of each torsion bar is connected to said movable means by at least one link which assume overcenter positions and further comprising unlocking means on said support for releasing said links from their overcenter positions.

10. A circuit breaker according to claim 2 wherein the fixed end of said torsion bar is L-shaped and engages a hole in one of said frame members.

11. A circuit breaker according to claim 3 wherein the fixed end of said torsion bar is L-shaped and engages a hole in said single frame member.

12. A circuit breaker according to claim 3 wherein the fixed end of said torsion bar is U-shaped and engages two holes provided in a plate which is transversely attached to said single frame member.

13. A circuit breaker according to claim 3 including a plate transversely attached to said single frame member, a projection extending from said plate, an eyebolt extending from said plate, and another eyebolt extending from said projection, said eyebolts engaging the fixed end of said torsion bar which is U-shaped.

14. A circuit breaker according to claim 13 wherein said eyebolts are adjustable. 

1. In a circuit breaker having supporting means comprising at least one frame member and movable crank means movable toward one position to effect movement of contact operating means in one direction, said crank means being movable to another releasably latchable position which allows the contact operating means to move in another direction, the combination of at least one torsion bar having at least one portion fixed with respect to said supporting means and having a rotatable portion for cooperation with said crank means, said torsion bar being chargeable by movement of said crank means to said other position and said torsion bar effecting movement of said crank means to said one position when the latter is released, said rotatable portion of said torsion bar being rotatable transversely to the direction in which said crank means moves.
 2. A circuit breaker according to claim 1 wherein said supporting means comprises a pair of spaced-apart frame members, wherein said contact operating means is disposed substantially between said frame members, and wherein said torsiOn bar is disposed between said frame members.
 3. A circuit breaker according to claim 1 wherein said supporting means comprises a single frame member, wherein said contact operating means is disposed substantially on either side of said frame member, and wherein said torsion bar is disposed on one side of said frame member.
 4. A circuit breaker according to claim 3 comprising two torsion bars disposed on opposite sides of said frame member.
 5. A circuit breaker according to claim 2 wherein said torsion bar carries a roller on its working end for engagement with a trunnion block on said movable means.
 6. A circuit breaker according to claim 4 wherein each of said torsion bars carries a roller on its working end for engagement with a trunnion block on said movable means.
 7. A circuit breaker according to claim 3 wherein the working end of said torsion bar is connected to said movable means by at least one link.
 8. A circuit breaker according to claim 7 wherein said link assumes an overcenter position with respect to said torsion bar and said movable means when said movable means is moved to said one position and further comprising unlocking means on said support for releasing said link from its overcenter position.
 9. A circuit breaker according to claim 4 wherein the working end of each torsion bar is connected to said movable means by at least one link which assume overcenter positions and further comprising unlocking means on said support for releasing said links from their overcenter positions.
 10. A circuit breaker according to claim 2 wherein the fixed end of said torsion bar is L-shaped and engages a hole in one of said frame members.
 11. A circuit breaker according to claim 3 wherein the fixed end of said torsion bar is L-shaped and engages a hole in said single frame member.
 12. A circuit breaker according to claim 3 wherein the fixed end of said torsion bar is U-shaped and engages two holes provided in a plate which is transversely attached to said single frame member.
 13. A circuit breaker according to claim 3 including a plate transversely attached to said single frame member, a projection extending from said plate, an eyebolt extending from said plate, and another eyebolt extending from said projection, said eyebolts engaging the fixed end of said torsion bar which is U-shaped.
 14. A circuit breaker according to claim 13 wherein said eyebolts are adjustable. 